Jonathan’s main research interest is in the design, conduct, analysis and reporting of randomised controlled trials, particularly surgical trials. His specific areas of interest include the specification of the target difference in the sample size calculation, addressing interventional expertise and methods for improving recruitment. Jonathan has extensive experience in systematic reviews of randomised controlled trials and diagnostic research. He has collaborated on numerous projects, including randomised trials, observational and diagnostic studies, methodological projects and systematic reviews in a variety of clinical areas, such as anaesthesia, cardiovascular research, obstetrics and gynaecology, ophthalmology, orthopaedics, primary care, general surgery and urology. Particular methodological contributions have been in the design and analysis of surgical trials (including the handling of surgical expertise and addressing non-compliance to treatment allocation), and also specifying the target difference in definitive ("Phase III") randomised trials. A news article related to the DELTA2 guidance, of which a summary paper was published in the BMJ and Trials journals, is available here.